The purpose of this project is to design a survey which would measure the prevalence, and describe the demographic characteristics of, major types of headache. The survey would also identify the clinical and environmental risk factors which may be associated with these headaches, and determine the impact of headaches on society. The survey questionnaire, which includes sections on demography, medical information and history, and cost, etc., has been developed. In the Feasibility Study (Phase 1), patients from four well-respected headache clinics have been solicited for a telephone interview about their headache problems. Information in the physician files about the headaches has been abstracted, coded, and computerized. This will be used as a basis for the investigation of validity of the telephone data. Plans for an Area Survey (Phase 2) have also been made.